DESCRIPTION: (Adapted from the Applicant's Abstract.) The major long-term objective of this proposal is to combine three ABR techniques that will help to delineate objectively and quantitatively the relationship between ABRs and peripheral hearing loss. This combination of techniques will allow evaluation of ABRs initiated from specific regions of the cochlea, specify error rates of threshold measures, reduce the variability of response parameter measurements, and optimize clinical test time. The three ABR techniques to be combined are a masking one for measuring the cochlear-place specific ABRs, a statistical one for objectively defining ABR threshold based on response properties rather than visual interpretation, and a weighted averaging one based on Bayesian principles using estimates of the background noise. A second long-term objective is to find an independent ABR threshold measure that can be used simultaneously with the above combinations to improve detection rates without compromising false-positive error rates. The third long-term objective is to develop these techniques to run on a micro-computer-based system to facilitate widespread clinical use. Six specific aims of the proposed research focus on evaluating normal and hearing-impaired patients with the combination of techniques, delineating the effects of stimulus parameters, evaluating methods to minimize the noise in the averages, and evaluating the joint use of other independent objective ABR measures to improve detection. The proposed work may fill critical, unmet needs in the current clinical use of ABRs for diagnostic information by providing a better understanding of the complex relationship between perceptual and electrophysiological measures in hearing-impaired patients, maximizing the averaging efficiency, and developing a truly objective, quantitative and consistent ABR method for estimating the audiogram and measuring response parameters.